Battery wiring issue

[jen1722terry]

Quick question:

We have two house batteries. One presently has one ground cable attached to it, the other has 4 ground cables attached - which makes for a very crowded terminal post.

My questions is: does it mater which house battery we ground our new refrigerator to? We'd like to ground it to the battery with only one ground cable attached.

FYI, if it matters, the two house batteries are Odessy AGM group 31, nearly new.

Looking forward to knowledge

Jenn and Terry

[Capt Hook]

Not if the batteries are in parallel which I would assume they are.

[Tom Keevil]

You could install a busbar, connecting all the grounds to that, and have only one wire to your battery.

[jbenagh]

The refrigerator won't care but to extend the life of your batteries, assuming they are 12V and wired in parallel, you should take positive off one battery and ground off the other. Otherwise the battery that is connected to both ends up taking somewhat more load and more charge and wearing out earlier than the other and more so as they become more imbalanced.

The bus bar is very useful for connecting up all the high current grounds.

Jeff

[Paul D.]

I second the bus bar concept. I wired mine that way in 2003 and it has worked great ever since.

[jen1722terry]

Thanks so much for the input, kind sailors.

The busbars are the obvious solution, which we've considered. However, the PO put our batteries under the cockpit and are hard for this creaky-backed sailor to reach, so I'm looking for and easier solution.

It may be best to get one of the rare (over here in Nova Scotia) marine electricians to redesign the battery wiring, also installing fusing near or on each battery.

jbnagh's idea to run only one mail cable from each of the two batteries is very interesting. We'll give that much thought.

Thanks again, and do enjoy the summer sailing season,

Jenn and Terry

[CD_Sailor]

The refrigerator won't care but to extend the life of your batteries, assuming they are 12V and wired in parallel, you should take positive off one battery and ground off the other. Otherwise the battery that is connected to both ends up taking somewhat more load and more charge and wearing out earlier than the other and more so as they become more imbalanced ...

I probably don't understand your comment well enough, but it seems that if the fridge is only connected to a particular battery (regardless of ground location) then the fridge can only operate when that battery is in use. What am I missing here?

[CD_Sailor]

Quick question:

We have two house batteries. One presently has one ground cable attached to it, the other has 4 ground cables attached - which makes for a very crowded terminal post ... does it mater which house battery we ground our new refrigerator to? ...

If you are connected to "ground," it makes no difference which battery is used. If this were not true and the grounds were "different" (i.e., at different voltages), then they would not really be "ground," would they.